In Von Holdt U.S. Pat. Nos. 3,909,180; 4,004,448, and 4,487,564, various systems are disclosed for retaining multiple piece molds and dies together while they are being lifted or otherwise manipulated. Additionally, in Von Holdt U.S. application Ser. No. 904,618, filed Sept. 8, 1986 and entitled Mold Pin Lock, another system is disclosed in which the application of a hook to a closed pair of mold halves at its lifting site prevents the opening of the mold until the hook is removed.
Molds and dies are often large and heavy. Accordingly, potentially severe accidents can take place, for example, while a mold is being lifted, when the user has forgotten to secure the mold pieces together in some manner. n that situation, one of the mold pieces which is not in contact with the lifting hook can slip loose and fall to the floor. The damage to the mold or die can result in thousands of dollars. Additionally, the consequences can be fatal if a person is struck by such a large piece of steel.
In accordance with this invention, another improved safety lock system is provided for molds, dies, and equivalent devices, which are contemplated to be broadly included in the term "mold". By this invention, a mold can exhibit a fail safe aspect, in which a rotatable lifting handle cannot be rotated into its outwardly extending position, for engagement by a hook, unless the mold halves are properly closed. Additionally, the very act of rotating the lifting handle outwardly serves to lock the closed mold halves together, which locking is not released until the lifting handle is again rotated to its non-usable position, in which it is not outwardly extending, but lying against the mold.
Thus, in an industrial operation, the safety of the shop can be significantly improved, since it is not possible to lift the mold by means of its lifting handle unless it is properly closed, and the lifting handle cannot be put into a position to receive a lifting hook without locking the mold.
Accordingly, by this invention, workers in the shop cannot make a mistake in the lifting and other manipulation of a mold to cause accidental opening, as long as they are making use of the lifting ring or handle carried on the mold. Thus, greater assurance of safety is provided.